I built an orbotron a couple years back. The thing was an amazingly good upper body workout. Welded 2" schedule 40 steel pipe, bent into a 12 sided shape by one of those $60 harbor freight pipe benders. The pivots were just grade 5 bolts, but it moved suprisingly well on those. Downhill ski boots locked you in in the bottom, and there was a padded tubular steel cage around the waist. padded steel handles on the top. We had about 100 people ride it with no injuries.
Oh yeah, it had encoders on it and tracked to a flying type game projected on the wall. Also had a throttle slider by the right hand handle and a fire button on the left hand handle, both thumb operated. Prety fun project all told. Cost was about $500, not counting the computer hardware which we already had. *** Edited 10/29/2005 9:45:16 PM UTC by Comatose***